Heme/Lymph

Question 1

Porphyria cutanea tarda is do to a deficiency of what enzyme?

Answer 1

Uroporphyrinogen Decarboxylase

Question 2

Acute intermittent porphyria (AIP) is an autosomal dominant condition caused by deficiency of what?

Answer 2

Porphobilinogen (PBG) deaminase

Question 3

ALA synthase is downregulated by what?

Answer 3

Glucose and Heme

Question 4

How can direct measurement of RBC mass be used to differentiate absolute from relative erythrocytosis?

Answer 4

• An increased RBC mass = absolute erythrocytosis
• A normal RBC mass = relative erythrocytosis

Question 5

How can serum EPO levels help distinguish between primary and secondary erythrocytosis?

Answer 5

• Primary erythrocytosis is assoc. w/ low EPO levels i.e., myeloproliferative disorders such as polycythemia vera
• Secondary erythrocytosis is assoc. w/ high EPO levels i.e., chronic hypoxia from high altitudes, smoking, or COPD

Question 6

How can precursor B-ALL and precursor T-ALL be distinguished by immunophenotyping?

Answer 6

• B-ALL are positive for TdT + CD10 and almost always CD19
• T-ALL are positive for TdT + CD1a + CD2, CD3, CD4, CD5, CD7 and CD8

Question 7

What are Auer rods and what type of cancer are they most abundantly found in?

Answer 7

• Coarse rod-shapd intracytoplasmic granules found in the cytoplasm of myeloblasts that stain (+) for myeloperoxidase (MPO)
• Abundant in acute promyelocytic leukemia (M3)

Question 8

Older pt w/ pancytopenia, hepatosplenomegaly, tear drop cells on peripheral blood smear, and a “dry tap” upon bone marrow aspiration likely has what; what will be seen on BM biopsy?

Answer 8

• Primary myelofibrosis
• Diffusely fibrotic marrow w/ clusters of megakaryocytes: secrete TGF-beta causing fibroblasts to fill marrow with collagen

Question 9

Both hemoglobin S (HbS) and hemoglobin C (HbC) arise from what type of mutations?

Answer 9

• Missense mutations
• HbS: arises when nonpolar valine replaces (-) charged glutamate in beta globin chain
• HbC: arises when (+) charged lysine** replaces **glutamate residue in beta globin chain

Question 10

Why is Procalcitonin considered a unique acute phase reactant?

Answer 10

• Has both positive and negative properties; therefore levels can be used to suggest the etiology of an infection
• Levels rise in reponse to bacterial toxins
• Levels fall in response to viral infections

Question 11

Which finding as part of the red cell index is most specific for hereditary spherocytosis?

Answer 11

Increased mean corpuscular hemoglobin concentration (MCHC)

Question 12

What is the initial screening test for Giant Cell arteritis and how can a definitive diagnosis be made?

Answer 12

• Initial screen for CRP level or erythrocyte sedimentation rate (ESR)
• Definitive diagnosis made via temporal artery biopsy

Question 13

An elderly woman with headaches, muscular pain, and a rapid response to glucocorticoid therapy has the typical features of what?

Answer 13

• Giant Cell (Temporal) Arteritis
• Focal granulomatous inflammation centered on the media w/ intimal thickening, elastic lamina fragmentation, and giant cell formation

Question 14

50% of patients with Giant Cell (Temporal) Arteritis will also have what other manifestation?

Answer 14

Polymyalgia Rheumatica

Question 15

Small lymphoid cells with increased nuclei to cytoplasmic ratio and cleaved nuclei are commonly seen in which neoplasm?

Answer 15

Follicular Lymphoma

Question 16

Basophilic oval inclusions in mature neutrophils (Dohle bodies) are seen in what?

Answer 16

Peripheral smear of a leukemoid reaction i.e., toxic systemic illness, burns or myelodysplasia